Safety device for positioning of pattern drums in circular knitting machines

ABSTRACT

In a circular knitting machine first and second ratchet wheels which regulate the alternate clockwise and counterclockwise rotation of a knitting instrumentality selector drum, a safety device for ensuring accurate positioning of the drum, consisting of a pawl with two pawl fingers adapted to latch the ratchet wheels and an unlatching element which withdraws the pawl from the ratchet wheels and allows the drum to turn.

United States Patent [191 Guell I Mar. 19, 1974 [54] SAFETY DEVICE FOR POSITiONING OF 3,444,706 5/1969 I Hill et al. .i 66/154 R PATTERN DRUMS IN C R 3,587,253 6/197! Guell 66/50 B KNITTING MACHINES FOREIGN PATENTS OR APPLICATIONS [76] lnventor: Jose Maria Dalmail Guell, San 996,291 6/1965 Great Britain 66/50 B Bruno, 103, Badalona, Spain 22 Filed: J 19 1971 Primary Examiner-Wm. Carter Reynolds Attorney, Agent, or Firm-Parrott, Bell, Seltzer, Park [21] Appl. No.: 163,895 & Gibson 1 [52] US. Cl 66/50 B 57 B R T fg In a circular knitting machine first and second ratchet 0 6/75 wheels which regulate the alternate clockwise and counterclockwise rotation of a knitting instrumentality [56] Ref fences Cited selector drum', a safety device for ensuring accurate e positioning of the drum, consisting of a pawl with two I UNXTED AT PATENTS pawl fingers adapted to latch the ratchet wheels and 1 722989' 8/1929 Ar es 66/50 B X an unlatching element which withdlraws the pawl from the ratchet wheels and allows the drum to turn. irmay eta. 3,380,265 4/1968 Peberdy 66/50 B X 3 Claims, 5 Drawing Figures SAFETY DEVICE FOR POSITIONING or PAI'I'ERN DRUMS IN CIRCULAR KNITTING MACHINES BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to a safety mechanism for the positive positioning of selector drums in circular knitting machines whereby said drums are prevented from taking up incorrect positions, that is, positions not corresponding to the present positions in each case and which would give rise to false selections of the needles, as a result of inertia due to the operational rotational movements of said drums.

In view of the working speed of circular knitting machines, it has been seen that the safety arrangements made for the positioning of the pattern drums are insufficient and inefficient, as is the case, for example, where gripper brakes, etc., are used.

2. SUMMARY OF THE INVENTION This invention provides an interesting solution to the problem raised in that the ratchet wheels, which determine the rotation of the pattern drum in one direction or the other to situate it at will inthe relative operative position, are associated with a pawl which latches said ratchet wheels in order to stop the drum in the preset point, which pawl has unlocking means for its pawl fingers with respect to the ratchet wheels to allow these to perform their operative turns.

The unlatching means between the pawl fingers and ratchet wheels preferably is a separator member at-' tached to the pawl, which pushes said pawl out of engagement with the respective ratchet wheel.

The pawl separator member is actuated by the same cam as is used to rotationally drive the ratchet wheels associated with the pattern drum, which actuation is performed by overcoming the tension of a spring which tends to situate the pawl in a position of engagement with the wheel.

When the machine is stopped, the pawl fingers may be manually disengaged from the ratchet wheels by a sliding member which acts on a lever directly associated with said pawl, thereby facilitating manipulations of the pattern drum.

BRIEF DESCRIPTION OF THE DRAWINGS Other aimsand features of the invention will be disclosed in detail in the following description, with reference to the attached drawings in which:

FIG. 1 is a perspective view of a mechanism according to the invention;

FIG. 2 is an elevation view, partly schematic, of the mechanism in question applied to a Circular knitting machine;

FIG. 3 is a view from below of the mechanism of the invention in its latched position;

FIG. 4 is a fragmentary view similar to FIG. 3 showing the unlatched position; and

FIG. 5 is a plan view of a mechanism having a manual drum unlatching means in the operative and inoperative' positions.

DETAILED DESCRIPTION OF THE INVENTION A preferred arrangement in accordance with this invention is for the pattern drum 1 of a circular knitting machine to have ratchet wheels 3 and 4 associated with its shaft 2. A gear system drives these wheels which in turn determine the rotation of the drum 1 in one direction or the other as desired. Such an arrangement is the subject matter of U. S. Pat. No. 3,587,253, to which reference may be had to supplement the description given here.

As stated hereinbefore, safe stoppage of the drum at a precise set point is not consistently achieved since the drum is subject to the effects of inertia. Therefore, the present invention contemplates the inclusion of a pawl 5, having two pawl fingers 5A and 53 (see FIG. 2) which act on the wheels 3 and 4 mounted on a shaft 6 associated with the aforementioned shaft 2 of the drum 1 through a gear system.

The pawl 5 is mounted on a shaft 7 and has a spring 8 tending to force its pawl fingers 5A and 513 into engagement with one of the teeth of the respective wheels 3 and 4. The shaft 6 is mounted in a plate 9. The spring 8 is held across pins 10 and 11 of the pawl and plate respectively.

Separator member 12 is associated with the pawl to act on said pawl fingers under the action of the cams which operate the ratchet wheels 3 and 4 in the manner disclosed in U. S. Pat. No. 3,5 87,253. The action of the cams on the separator member is to move the pawl fingers from the latched position (FIG. 3) to the unlatched position (FIG. 4) so as to permit the selector drum to be rotated. It is contemplated that there may be a separator member 12 for each pawl finger or one for both. A base 13 holds all the elements comprising the mechanism and associated devices.- A screw 14 holds the plate 9 to the base 13.

As briefly pointed out above, the pawl 5 and associated mechanism include p'awl fingers 5a and 5b formed by bifurcations of the body of the pawl (FIG. 1). The'pawl 5 is supported for pivotal motion about the shaft 7, while the separator member 12 fitted between the bifurcations defining the pawl fingers 5a and 5b is supported for pivotal movement about the pin 10. Such relative pivotal movement of the pawl 5 and separator member 12 may be noted by comparing FIGS. 3 and 4. I

The invention also contemplates the inclusion of a manually operable sliding member 15 having a rib l6 and being associated with a stop pin 17 by way' of a cutaway portion 18. The sliding member 15 is associated with a lever 19 which, in turn, pivots about a mounting screw (FIG. 2) andoperates on a portion of the pawl 5 remote from the separation member 12 to unlatch the mechanism.

The mechanism shown in the figures includes a cog 20 mounted on shaft 2 of the drum 1 to which. the brake shoes of some jaws 21 are applied to resist the rotation of the drum. Such jaws 21 are pulled against the cog by a spring 22 mounted between pins 23 and 24 and are movable between active or inactive positions by a bolt 25. I

The shaft rotation gear system for the drum 1 ineludes: two gear wheels 26A and 26B mounted on and around the shaft 6; an intermediate pinion 27, mounted on a shaft 28; and the cog 20. The function of the system is to produce rotation of the drum in one direction or the other by way of operation of the ratchet wheels 3 or 4 as described, for example, in U. S. Pat. No. 3,587,233.

The mechanism operates as follows: As shown in the ratchet wheels 3 and 4, urged by the spring 8, which corresponds to the latched state of the mechanism.

To obtain the unlatched state, the pawl fingers A and 5B are withdrawn by the action of the separator member 12 which pushes the pawl 5 open so that they cease to operate on the wheels 3 and 4, that is, so that these can turn freely and the mechanical rotation system of the drum 1 can be set in movement.

In obtaining this operation of the separator member '12, it is contemplated that it be driven by the same cam normally used to drive the wheels 3 and 4 in known devices such as the arrangement of U. S. Pat. No. 3,587,253. A selected cam such as one of the cams 40, 40a (indicated in phantom lines in FIGS. 2 through 4) before operating on the wheels 3 and 4 strikes the separator member 12 on its edge 30. The selected one of the cams 40, 40a (which correspond to the cams 8, 8a of the arrangement of the aforementioned patent) engages the surface 30 of the separator member 12 in advance of engagement with the corresponding one of the wheels 3, 4. Such engagement between the edge 30 and the cam (for example a cam 40) imposes a force on the separator member (acting to the left in FIGS. 3 and 4) which causes toggle or scissor action of the separator member 12 and pawl 5 about the pivot axes defined by the pin 10 and the shaft 7. The separator member 12 acts on the pawl 5 and disengages it from the wheels by overcoming the resistence of the spring 8, whereby the pawl 5 leaves the wheels 3 and 4 free and the cam operates on them immediately thereafter. In any case, the pawl fingers 5A and 5B are taken out of operation by overcoming the opposition of the spring 8.

The present invention also contemplates, as has been mentioned hereinbefore, manual, unlatching of the drum 1 at will. The purpose of this is to allow for possible manipulations of the drum 1 for adjustment or other purposes. This action is obtained by pushing the sliding member 15 which causes separation of the pawl fingers 5A and'SB by the action of the lever 19.

-I claim:

1. In combination with a circular knitting machine having a knitting instrumentality selector drum mounted for rotation in alternate clockwise and counterclockwise directions, first and second ratchet wheels each operatively interconnected with said selector clockwise and counterclockwise rotation, and first and second movable cam means mounted on a movable part of the machine and adapted when in operative position for engaging corresponding ones of said first and second ratchet wheels for rotating said selector drum, a safety device for controlling positioning of said selector drum and comprising:

latching pawl means mounted for pivotal movement and for engaging said first and second ratchet wheels, said latching pawl means cooperating with said ratchet wheels when in engagement therewith for fixing said selector drum in a predetermined rotational position and for locking said selector drum against rotation in either of the alternate directions, biasing means for resiliently urging said latching pawl means into engagement with said ratchet wheels, and a separator member operatively connected to said latching pawl means and extending adjacent said first and second ratchet wheels for engagement by such one of said first and'second cam means as is in operative position and for displacing'said latch-,

ing pawl means against the urging of said biasing means and away from said ratchet wheels in response to engagement by said one cam means for unlocking said ratchet wheels and said selector drum and permitting driving of said selector drum. 2. A combination according to claim 1 wherein said latching pawl means has first and second pawl fingers each for engaging a corresponding one of said first and second ratchet wheels and further wherein said separator member extends between said pawl fingers and between said ratchet wheels engaged thereby.

3. The combination according to claim 1 further comprising:

manually operable means for engaging said latching pawl means independently of said separator member and for displacing said latching pawl means against the-urging of said biasing means and away from said ratchet wheels for manually unlocking said ratchet wheels and permitting manual rotation of said selector drum.

v UNITED STATES PATENT OFF-ICE CERTIFICATE OF CORRECTION Patent No. 3,797, 277 Dated March 19, 1974 lnv Jose Maria Dalmau Guell It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

In the Abstract, line 1, following "machine" insert --with-- Column 1, line 10,"presen should be --preset Column 2', line 47, "separation" should be -separator Column 2 line 63, "3, 587, 233" should be 3, 587, 253-- Signed and sealed this 16th day of July 1971;".

(SEAL) Attest:

McCOY M. GIBSON, JR. 7 C. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 60376-969 i 0.. .Nllllllf "mum: onucl: nu 0-in-1 FORM PO-IOSO ($69) 

1. In combination with a circular knitting machine having a knitting instrumentality selector drum mounted for rotation in alternate clockwise and counterclockwise directions, first and second ratchet wheels each operatively interconnected with said selector drum for respectively driving said selector drum in clockwise and counterclockwise rotation, and first and second movable cam means mounted on a movable part of the machine and adapted when in operative position for engaging corresponding ones of said first and second ratchet wheels for rotating said selector drum, a safety device for controlling positioning of said selector drum and comprising: latching pawl means mounted for pivotal movement and for engaging said first and second ratchet wheels, said latching pawl means cooperating with said ratchet wheels when in engagement therewith for fixing said selector drum in a predetermined rotational position and for locking said selector drum against rotation in either of the alternate directions, biasing means for resiliently urging said latching pawl means into engagement with said ratchet wheels, and a separator member operatively connected to said latching pawl means and extending adjacent said first and second ratchet wheels for engagement by such one of said first and second cam means as is in operative position and for displacing said latching pawl means against the urging of said biasing means and away from said ratchet wheels in response to engagement by said one cam means for unlocking said ratchet wheels and said selector drum and permitting driving of said selector drum.
 2. A combination according to claim 1 wherein said latching pawl means has first and second pawl fingers each for engaging a corresponding one of said first and second ratchet wheels and further wherein said separator member extends between said pawl fingers and between said ratchet wheels engaged thereby.
 3. The combination according to claim 1 further comprising: manually operable means for engaging said latching pawl means independently of said separator member and for displacing said latching pawl means against the urging of said biasing means and away from said ratchet wheels for manually unlocking said ratchet wheels and permitting manual rotation of said selector drum. 